Typically, for a plumbing fixture (e.g., a faucet, a tub spout, a shower head), a valve body conveys water flowing from a main water source to a desired destination (e.g., a sink, a tub, a basin). The valve body generally has two water inlet passages through which cold water and hot water from the main water source can respectively flow. The valve body also has a water outlet passage through which the cold water, the hot water or a mixture of the cold and hot water can be discharged to an outlet portion of the plumbing fixture (e.g., a spout). In a one-handle version of the valve body, the valve body has a cavity for receiving a valve cartridge which allows a user to control the flow rate and the temperature of the water flowing through the water inlet passages to the water outlet passage using a single valve actuating mechanism.
One type of (conventional) valve cartridge is a structural assembly including a housing in which two or more disks, plates or the like are disposed. The disks are generally made of a hard material (e.g., ceramic or metal). At least one of the disks (i.e., a fixed disk) is fixed with respect to the housing. Another of the disks (i.e., a movable disk) is disposed above the fixed disk and is movable with respect to the fixed disk. The valve cartridge includes the actuating mechanism that is directly or indirectly connected at one end to the movable disk. Another end of the actuating mechanism extends through an opening in the housing for manipulation by a user. The end of the actuating mechanism extending through the opening in the housing can be connected to an operating member, such as a handle, knob or the like, to assist the user in operating the valve cartridge.
In a one-handle version of this type of valve cartridge for use in the one-handle version of the valve body, the fixed disk includes two inlet openings (i.e., a cold water inlet opening and a hot water inlet opening) that substantially align with the water inlet passages of the valve body when the valve cartridge is installed in the valve body. Furthermore, the fixed disk includes an outlet opening that substantially aligns with the water outlet passage of the valve body when the valve cartridge is installed in the valve body. The actuating mechanism is connected to the movable disk via a coupling. The actuating mechanism can be pivoted to cause translational movement of the movable disk. The actuating mechanism can be rotated to cause angular movement of the movable disk.
In this manner, the movable disk can assume different positions with respect to the fixed disk. In particular, pivoting of the actuating mechanism changes the flow rate of the water from zero to a maximum flow rate, whereas rotation of the actuating mechanism changes the temperature of the water. Accordingly, a one-handle actuating mechanism can control both the flow rate and the temperature of the water flowing through the valve cartridge.
The valve cartridge also includes one or more seals for preventing water from leaking out of the valve cartridge. The seals can be located, for example, below, between and/or above the disks in the valve cartridge. When the valve cartridge is installed in the valve body, a retention nut is used to secure the valve cartridge in the valve body. The retention nut engages the housing of the valve cartridge such that the seals in the valve cartridge are compressed and, thus, apply a loading force to the components (including the disks) in the valve cartridge. As a torque applied to the retention nut increases, the load on the components in the valve cartridge increases. Accordingly, the fixed disk and the movable disk are kept in water tight contact after installation of the valve cartridge in the valve body.
During installation of the conventional valve cartridge in the valve body, it is typically required that a load within a specified range be applied to the valve cartridge to insure proper operation of the valve cartridge. Consequently, a torque within a specified range must be applied to the retention nut to achieve a proper load on the valve cartridge.
If an insufficient load is applied to the valve cartridge, such as from too little torque being applied to the retention nut, the valve cartridge will not operate properly. For example, if inadequate torque is applied to the retention nut during installation of the valve cartridge, the seals in the valve cartridge are not compressed sufficiently to insure that the fixed disk and the movable disk are kept in water tight contact after installation of the valve cartridge in the valve body, such that the valve cartridge is likely to leak. Additionally, the insufficient compression of the seals in the valve cartridge can cause the components in the valve cartridge to engage one another loosely or improperly. For example, if a frictional force between the disks (under the load of the retention nut) is too small, the frictional force can be insufficient to keep the operating member in a raised (i.e., on) position, thereby resulting in a problem known as “handle drop.” As a result of these problems resulting from an insufficient installation load, the user can experience an inconsistent, imprecise and/or rough feel during operation of the valve cartridge.
If too great a load is applied to the valve cartridge, such as from an excessive torque being applied to the retention nut, it will be difficult for the user to operate the valve cartridge (e.g., the movable disk will be hard to move relative to the fixed disk). In an extreme case, the movable disk will not move relative to the fixed disk, thereby rendering the valve cartridge inoperable. Furthermore, if an excessive load is applied during installation of the valve cartridge, a resulting increased frictional force needed to move the movable disk on the fixed disk is transferred up to the actuating mechanism of the valve cartridge, where it is felt by the user. Further still, the excessive load on the valve cartridge can result in accelerated wear of the various dynamic bearing surfaces in the valve cartridge, thereby shortening the effective life of the valve cartridge. As a result of these problems resulting from an excessive installation load, the user can experience an inconsistent, imprecise and/or rough feel during operation of the valve cartridge.
Accordingly, a specialized tool (e.g., a torque wrench) or some other specialized mechanism is necessary for properly installing the conventional valve cartridge in the valve body.
Consequently, there is a need in the art for a valve cartridge wherein operation of the valve cartridge is insensitive to a load applied to the valve cartridge during installation of the valve cartridge in a valve body.